Intratumoral Activation of 41BB Costimulatory Signals Enhances CD8 T Cell Expansion and Modulates Tumor-Infiltrating Myeloid Cells.

The activation of 41BB costimulatory signals by agonistic Abs enhances the expansion and function of tumor-infiltrating lymphocytes (TILs) for treating cancer patients with adoptive cell therapy. However, the impact of 41BB agonism is not limited to enhancing the activity of T cells, and the mechanism by which additional activation of this costimulatory axis in tumor-associated myeloid cells is poorly understood. In this study, we describe that the intratumoral administration of 41BB agonistic Abs led to increases in CD8 T cell infiltration followed by tumor regression in murine models. We found that granulocytes and monocytes rapidly replaced macrophages and dendritic cells in tumors following administration of anti-41BB Abs. Overall, myeloid cells from anti-41BB-treated tumors had an improved capacity to stimulate T cells in comparison with control-treated tumors. In human coculture systems, we demonstrated that the agonism of the 41BB-41BBL axis enhanced costimulatory signals and effector functions among APC and autologous TILs. Overall, these findings suggest that the effect of 41BB agonistic Abs are supported by additional costimulatory signals from tumor-associated myeloid cells,v leading to enhanced TIL expansion and function.

Intralesional injection of rose bengal augments the efficacy of gemcitabine chemotherapy against pancreatic tumors.

BACKGROUND: Chemotherapy regimens that include the utilization of gemcitabine are the standard of care in pancreatic cancer patients. However, most patients with advanced pancreatic cancer die within the first 2 years after diagnosis, even when treated with standard of care chemotherapy. This study aims to explore combination therapies that could boost the efficacy of standard of care regimens in pancreatic cancer patients. METHODS: In this study, we used PV-10, a 10% solution of rose bengal, to induce the death of human pancreatic tumor cells in vitro. Murine in vivo studies were carried out to examine the effectiveness of the direct injection of PV-10 into syngeneic pancreatic tumors in causing lesion-specific ablation. Intralesional PV-10 treatment was combined with systemic gemcitabine treatment in tumor-bearing mice to investigate the control of growth among treated tumors and distal uninjected tumors. The involvement of the immune-mediated clearance of tumors was examined in immunogenic tumor models that express ovalbumin (OVA). RESULTS: In this study, we demonstrate that the injection of PV-10 into mouse pancreatic tumors caused lesion-specific ablation. We show that the combination of intralesional PV-10 with the systemic administration of gemcitabine caused lesion-specific ablation and delayed the growth of distal uninjected tumors. We observed that this treatment strategy was markedly more successful in immunogenic tumors that express the neoantigen OVA, suggesting that the combination therapy enhanced the immune clearance of tumors. Moreover, the regression of tumors in mice that received PV-10 in combination with gemcitabine was associated with the depletion of splenic CD11b+Gr-1+ cells and increases in damage associated molecular patterns HMGB1, S100A8, and IL-1α. CONCLUSIONS: These results demonstrate that intralesional therapy with PV-10 in combination with gemcitabine can enhance anti-tumor activity against pancreatic tumors and raises the potential for this strategy to be used for the treatment of patients with pancreatic cancer.

Treatment Outcomes for Periprosthetic Femoral Fractures in Cementless Press-Fit Total Hip Replacement.

OBJECTIVE: The aim of this study was to report outcomes in dogs with periprosthetic femoral fractures associated with a press-fit cementless femoral total hip replacement implant. MATERIALS AND METHODS: Electronic medical records and digital radiographs were used to identify dogs with periprosthetic femoral fractures associated with press-fit cementless total hip replacement. Data collected included signalment, weight, time of fracture, cause of fracture, presence of intra-operative fissure, fracture type, repair technique, and clinical and radiographic outcomes. Long-term patient outcome was assessed by communication with owners or referring veterinarians. RESULTS: Twenty-eight dogs with femoral fracture repair associated with cementless press-fit total hip replacement were identified. Eight of the fractures occurred intraoperatively and 20 occurred at a median of 2 days postoperatively. An oblique or spiral configuration was noted in 19 cases and 15 occurred at the distal end of the femoral stem (type B), with thirteen type B1, one type B2 and one type B3 fractures. Fractures were repaired with non-locking (18/28) or locking-plate fixation (10/28). Cerclage wire was applied around the plate and proximal bone segment in 17/28 dogs. Major complications occurred in 7/28 cases (five deep infection, two mechanical failures). Bone healing was noted in 21/23 cases, for which follow-up radiographic interpretation was available. Return to function was complete in 17 cases, acceptable in 8 cases and unacceptable in 3 cases. CONCLUSIONS: While cementless total hip replacement periprosthetic femoral fractures can be successfully repaired with lateral plate fixation, the risk of infection appears to be high.

Complications of porous-coated press-fit cementless total hip replacement in dogs.

OBJECTIVE: To report postoperative complications using a commercially available porous-coated press-fit cementless total hip replacement (THR) system in dogs. METHODS: Medical records were reviewed for client-owned dogs with hip pathologies requiring THR. A minimum of six-week postoperative orthopaedic examination and orthogonal pelvic radiographs were used to assess outcome and complications in the perioperative period. Referring veterinarian medical records, phone interviews with clients, or both were used to assess long-term functional outcome and complications. RESULTS: Bilateral THR was performed in 36 dogs, and unilateral in 147 dogs, making a total of 219 THR procedures in 183 dogs. A total complication rate of 31.1% (68/219) was observed. A catastrophic complication was observed in 8.2% (n = 18), a major complication in 9.6% (n = 21), and a minor complication in 13.2% (n = 29) of procedures. The most common complications were intra-operative femoral fissure (n = 46), diaphyseal femoral fracture (n = 15), and coxofemoral luxation (n = 9). Full return to function was achieved in 88.1% of procedures with a median follow-up period of 42 months. CLINICAL SIGNIFICANCE: Porous-coated press-fit cementless collarless total hip replacements have a high complication rate. The majority of complications occur intra-operatively or perioperatively, with few complications occurring beyond 12 weeks postoperatively. Both fissure fractures and diaphyseal femoral fractures carry a favourable prognosis with immediate cerclage wiring and plate fixation, respectively.

Evaluation of fluid production and seroma formation after placement of closed suction drains in clean subcutaneous surgical wounds of dogs: 77 cases (2005-2012).

OBJECTIVE: To evaluate fluid production and factors associated with seroma formation after placement of closed suction drains in clean surgical wounds in dogs. DESIGN: Retrospective case series. ANIMALS: 77 client-owned dogs with a subcutaneous closed suction drain placed following a clean surgical procedure. PROCEDURES: Medical records (January 2005 to June 2012) were reviewed, and signalment, site of surgery and underlying disease process, histologic evaluation results, total drain fluid production, fluid production rate (mL/kg/h) at 12-hour intervals, cytologic evaluation of drain fluid, and development of dehiscence, infection, or seroma were recorded. Associations among variables were evaluated. RESULTS: The most common complication was dehiscence (n = 18), followed by seroma (14) and infection (4). Dogs that developed a seroma had significantly greater total drain fluid volume relative to body weight and greater fluid production rate at 24 and 72 hours as well as the last time point measured before drain removal. Dogs in which drains were removed when fluid production rate was > 0.2 mL/kg/h (0.09 mL/lb/h) were significantly more likely to develop a seroma. CONCLUSIONS AND CLINICAL RELEVANCE: Seroma formation was more common in dogs with a higher rate of fluid production relative to body weight, but was not associated with the number of days that a closed suction drain remained in situ. Dogs may be at greater risk of seroma formation if their drains are removed while drainage is still occurring at a rate > 0.2 mL/kg/h.

Francisella noatunensis subsp. orientalis pathogenesis analyzed by experimental immersion challenge in Nile tilapia, Oreochromis niloticus (L.).

Francisella noatunensis subsp. orientalis (Fno) (syn. F. asiatica) is an emergent warmwater fish pathogen and the causative agent of francisellosis in tilapia (Oreochromis sp). To study the pathogenesis of this bacterium, tilapia fingerlings were experimentally infected by immersion challenge with wild type (WT) Fno and the distribution of bacteria to multiple organs, as well as associated lesion development, investigated after 3, 24, 48, 96, and 192h by real-time PCR and histopathological examination. Surface mucus collected 3h post-infection contained the highest number of Fno genome equivalents (GE). After 96h, marked increases of WT Fno GE were detected in spleen, anterior kidney, posterior kidney, gill, heart, liver, brain, gonad, and the gastrointestinal tract. Increases in bacterial GE also corresponded to the appearance, size and number of granulomas typical of francisellosis, predominantly in the spleen and anterior and posterior kidney segments. A simultaneous comparison was also made in tilapia challenged with an attenuated Fno strain containing a mutation in the intracellular growth locus C (iglC) gene, essential to intracellular survival. Compared to the WT, the mutant iglC strain was present in most tissues in similar numbers prior to 48h post-challenge. While the mutant did not replicate significantly or produce lesions in any tissue, it persisted for up to 192h. These findings provide insight into the pathophysiology of francisellosis in tilapia, which may also prove useful as a model for the study of mammalian tularemia, and advance our understanding of the utility of the ΔiglC mutant as a potential vaccine candidate.